07:Posttest 07.Cherical Reactions
3. For a reaction to occur, energy must be
to break chemical bonds.
O released
absorbed
ons
converted

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.

4d^55s^1 ( third choice)